Energy Calculator

A Short Lesson in Electricity
Amps x Volts = Watts
Watts / Volts = Amps
Watts / Amps = Volts
Kw = 1,000 Watts

Electricity is the flow of electrons through a conductor like a wire. It’s like the flow of water through a pipe. To increase the flow of water through a pipe you need either a larger pipe or more pressure. The pressure in an electrical system is called voltage and is measured in volts. The higher the voltage in a system the more force behind it.
In a water pipe the size of the pipe also determines the rate of flow. The bigger the pipe the greater the flow. The amount of flow in electricity is called amperage, measured as amps or current. Electrical “power” is a combination of the pressure, or VOLTAGE times the flow, or AMPERAGE. This combination is called the WATT or WATTS. This is generally the unit of power that we use in assessing electrical systems. It functions as a common denominator for different voltages and amperages. For
example:
5 amps at 24 Volts = 120 Watts (Amps x Volts = Watts)
or
1,500 watts / 120 Volts = 12.5 amps (Watts/ Volts = Amps)

One watt that is powered for one hour is called one WATT HOUR. 1,000 watts use for one hour is a KILOWATT HOUR.
These formulas help us figure out how much solar power it will take to run our loads:

A 4 amp motor running for 1/2 hr. at 120 volts uses 240 watts.
4(amps) x 120(volts)=480 watts / 2 (1/2 hr.) = 240 Watt hrs.

A 100 watt solar panel produces 100 watt hours per full solar hour. It would take about 2 1/2 hours for that solar panel to run the motor for 1/2 hour. This is a simplistic example because there are various inefficiencies in solar electric systems, but this is a good “rule of thumb”. Phantom Loads Don’t pay for electricity that you aren’t using. Phantom loads are the electricity that appliances use when they are turned OFF! That’s right...


Appliance

Watts

Appliance

Watts

Appliance

Watts

Central Air Conditioner NA

5,000

Electric blanket

200

Hedge trimmer

450

Electric Clothes Dryer NA

3,400

Shaver

15

Weed eater

500

Oven

3,000

Waterpik

100

1/4” drill

250

Hair Dryer

1,538

Well Pump (1/3-1 HP)

480-1200

1/2” drill

750

Dishwasher

1200-1500

Laptop

60-250

1” drill

1000

Coffee Machine

1,500

Plasma TV

339

9” disc sander

1200

Microwave

1,500

LCD TV

213

3” belt sander

1000

Popcorn Popper

1,400

25” color TV

150

12” chain saw

1100

Toaster oven

1,200

19” color TV

70

14” band saw

1100

Hot Plate

1200

12” black and white TV

20

7-1/4” circular saw

900

Iron

1,100

Stereo

10-30

8-1/4” circular saw

1400

Toaster

1,100

Satellite dish

30

Refrigerator/ Freezer**

Microwave

500-1500

Radiotelephone - Receive

5

20 cu. ft. (AC)

1411 watt-hours/day*

Room Air Conditioner NA

1,100

Radiotelephone - Transmit

40-150

16 cu. ft. (AC)

1200 watt-hours /day*

Vacuum Cleaner

500

Lights

 

Freezer

Water heater

479

100 watt incandescent bulb

100

15 cu. ft. (Upright)

1240 watt-hours /day*

Sink Waste Disposal

450

25 watt compact fluor. bulb

28

15 cu. ft. (Chest)

1080 watt-hours /day*

Espresso Machine

360

50 watt DC incandescent

50

Cell Phone - recharge

2-4 watts

Dehumidifier

350

40 watt DC halogen

40

MP3 Player - recharge

.25-.40 watts

Blender

300

20 watt DC compact fluor.

22

* TV’s,VCR’s and other devices left plugged in, but not turned on, still draw power.

**To estimate the number of hours that a refrigerator actually operates at its maximum wattage, divide the total time the refrigerator is plugged in by three. Refrigerators, although turned "on" all the time, actually cycle on and off as needed to maintain interior temperatures.

Humidifier

300-1000

CFL Bulb (60-watt equivalent)

18

Video Game Player

195

CFL Bulb (40-watt equivalent)

11

Standard TV

188

CFL Bulb (75-watt equivalent)

20

LCD Monitor

80-150

CFL Bulb (100-watt equivalent)

30

Desktop Computer (Standard home/business)

80-120

Heaters***

 

Desktop Computer (Gaming)

400-1000+

Laptop Computer

40-120

Portable Fan

100

Engine Block Heater NA

150-1000

Ceiling Fan

100

Portable Heater NA

1500

Can Opener

100

Waterbed Heater NA

400

Curling Iron

90

Stock Tank Heater NA

100

Stereo

60

Furnace Blower

300-1000

Cable Box

20

Clothes Dryer - Gas Heated

300-400

Clock Radio

7

Well Pump (1/3-1HP)

480-1200